The automotive industry has a critical requirement for accurate timing and guaranteed data delivery to ensure passenger safety and a seamless customer experience. Autonomous vehicles utilize advanced SoC architectures in the automotive ecosystem to address mission critical processing and timing requirements, increasing the importance of Time Sensitive Networking (TSN) features in automotive ethernet.
In our previous blogs on this subject we discussed the evolution and impact of Audio-Video Bridging (AVB) specifications. In this blog we will take a closer look at each of the TSN specifications and analyze what these offer to the AVB-TSN applications.
Components of TSN:
802.1Qbu, 802.3br (Frame pre-emption):
IEEE 802.1Qbu, together with IEEE 802.3br, works on a standard pre-emption mechanism. To implement low latency for critical data, data is classified into Express and Regular traffic. Express data frames suspend the transmission of preemptable (regular) frames. This allows standard Ethernet frames to be interrupted to allow the transmission of high-priority frames.
802.1Qbv (Time-Aware Shaping (per-queue based)):
Time-Aware Shaping (802.1Qbv) is critical for providing delivery of TSN frames on-time. Qbv defines a mean to transmit certain TSN Ethernet frames on a schedule, while allowing non-TSN Ethernet frames to be transmitted on a best effort basis around the TSN frames.
802.1Qcc (Stream Reservation Protocol (SRP) Enhancements):
The Stream Reservation Protocol (802.1Qat) utilizes Multiple Stream Registration Protocol (MSRP) to establish stream reservations across a bridged network. It has been accepted by Automotive/Industrial markets. IEEE 802.1Qcc improves existing reservation protocols such as SRP with addition of a set of TSN enhancements and extends the capabilities of SRP.
802.1Qat (Stream Reservation Protocol):
Data streams requiring guaranteed Quality of Service (QoS) in Local Area Networks (LANs) use Stream Reservation Protocol (SRP) to signal and register their network usage requirements before beginning transmission of frames. Thus, it allows network resources to be reserved for specific traffic streams in a network.
802.1Qci (Per-Stream Filtering and Policing):
802.1Qci provides mechanism to filter frames on ingress ports based on arrival times, rates, and bandwidth. A packet is dropped if that packet from the flow arrives out of scheduled “window” for it. Robustness of a network is improved by policing and filtering.
802.1AS-rev (Timing and Synchronization for Time-Sensitive Applications (gPTP)):
Generalized Precision Time Protocol (gPTP) is used to synchronize clocks throughout a computer network. It provides an accurate time base to all time-aware elements in an Ethernet network and maintains a common sense of time.
Ethernet AVB/TSN Verification Challenges and Synopsys Solutions:
Keeping pace with fast evolving specifications and addendums:
Industry first for all major specifications – IEEE802.1AS, IEEE802.1Qbu/IEEE802.3br, IEEE802.1CB, IEEE802.1Qav, IEEE802.1Qbv, IEEE802.1Qci, IEEE 172-2016, IEEE 1588 v1/v2. Synopsys VIP provides flexibility to preempt the preemptable queue at any desired point. It also checks and collects all these fragments in correct order on the receive side.
Capability to generate mix of CTAG over RTAG frames and other frames for 802.1CB verification. Tracks AVB credits (Idle/Send slope) on per queue basis, notifies the user if threshold is reached and help 802.1Qav verification. Dynamic configurability to open/close the gates for 802.1Qbv, Qci verification. Ability to generate various PTP v1/v2 frame types along with dynamic timestamps insertion.
Verification completeness and quality
Collaboration with standard bodies and partners. Thorough verification with silicon proven Synopsys IPs and easy to integrate Testsuite covering all major specifications for faster closure on Verification.
Uniform solution for various interfaces
Synopsys AVB/TSN support exist for all speed modes including RMII 10/100M, USXGMII. It also supports interface switching dynamically.
Coverage and Debug
Native Integration with Verdi Protocol Analyzer, trace files, debug ports, detailed error message. Built in extensive coverage model (with an option for extension to user) and Verification Plans help users to get more confidence on verification completeness.
Compliance and Certification
ISO 26262 functional safety compliant protocol verification process. Synopsys tools are certified to ISO 26262 ASIL D to accelerate quality and functional safety qualification.
Automotive Ethernet applications are driving the needs for faster and accurate data transmission features in the protocol. As we discussed, these fast evolving specifications have made the protocol verification process challenging, therefore Synopsys end-to-end protocol verification solutions for , AVB, Base T, and FlexE provide a comprehensive set of protocol, methodology, verification and productivity features, enabling users to achieve accelerated verification closure of Ethernet based designs. Synopsys is collaborating with early customers and partners to extend the standard architecture for their next-generation designs with new features available now with latest specifications.
Synopsys VIP is natively integrated with the Synopsys Verdi® Protocol Analyzer debug solution as well as Synopsys Verdi® Performance Analyzer. Running system-level payload on SoCs requires a faster hardware-based pre-silicon solution. Synopsys transactors, memory models, hybrid and virtual solutions based on Synopsys IP enable various verification and validation use-cases on the industry’s fastest verification hardware, Synopsys ZeBu® emulation and Synopsys HAPS® prototyping systems.
To learn more about Synopsys Ethernet VIP and Test Suites please visit http://synopsys.com/vip